Blends of Fullerene Derivatives, and Uses Thereof in Electronic Devices

Abstract

Disclosed are compositions of mixed fullerene derivatives with utility in organic semiconductors, and methods of making and using such compositions. In certain embodiments, the present invention relates to compositions of mixed fullerene derivatives further comprising one or more additional fullerene-based components within specified ranges. In certain other embodiments, the invention relates to methods of producing mixed fullerene derivatives of a specific composition from mixed fullerene starting materials, or pure fullerene derivatives of a specific composition from mixed fullerene derivatives. In yet other embodiments, the invention relates to semiconductors and devices comprising a composition of the invention.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60 / 818,888, filed Jul. 6, 2006.BACKGROUND OF THE INVENTIONFullerene Derivatives[0002]Significant progress has been made in the development of thin-film organic electronic devices, such as photovoltaic cells, transistors, photodetectors, sensors, and other devices for commercial application. Many of these devices utilize solution-processable semiconductors based on fullerene derivatives in pure form. The most commonly used fullerene derivative is Phenyl-C61-Butyric-Acid-Methyl-Ester ([60]PCBM) (Scharber et al., Advanced Materials (18) 789-794), which is classified as a methanofullerene. Another methanofullerene derivative is Thiophenyl-C61-Butyric-Acid-Methyl-Ester ([60]ThCBM).[0003]Methanofullerenes possess many benefits compared to the native (un-derivatized) fullerene in organic electronics applications. One benefit is their increased processability compared to...

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Problems solved by technology

Therefore, higher degrees of amorphous nature (i.e., lower crystallinity) lead to reductions in electron mobility and corresponding reductions in energy conversion efficiency for organic electronic devices.

Virtually all organic electronic devices utilize a single n-type semiconductor because certain impurities in the ppm level or even ppb level can drastically alter device performance.

For example, impurities in the ppm level or even ppb level can drastically alter device performance for silicon-based electronics.

However, impurities can alter the electronics of the device for other reasons, including short-circuiting and electron trapping.

Thin-film organic electronics device performance depends on a large set of processing and materials parameters, with a high degree of complexity in the interaction of these parameters to make up the final device morphological and electronics properties.

It is often not possible to predict the effect that a change in the molecular structure of an n-type semiconductor fullerene derivative will have on the final organics electronics device performance, even knowing the reduction potential, absorption properties, and other electronic properties.

This is mainly due to the fact that the impact on the physical disorder to of the resulting thin-film multi-phase system is difficult to predict a priori.

Likewise, a change in type and level of impurities present in a given fullerene derivative n-type semiconductor may affect the morphology and electronics properties and resulting device performance of a thin-film device in an unpredictable manner.

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